Mobile communication network provides communication services to subscribers residing in an operational area of the mobile communication network in question. The mobile communication network may be divided to two sub-entities i.e. a core network (CN) and a radio access network (RAN). The radio access network provides the communication services over radio signals to subscribers, i.e. communication terminals, under control of the core network.
The core network has a plurality of tasks in the provision of communication services to the subscribers. For example, the core network performs authentication, call control/switching and charging related operations among other tasks. Subscriber management plays an important role in order to perform operations of the core network. The mobile communication network shall be aware of subscribers being served by the mobile communication network in question. For example, the following pieces of information shall be known:                subscribers, which are registered in the communication network in question        subscribers belonging to a certain network (i.e. to so called home network), which are served by some other mobile communication network (i.e. roaming)        subscriber location        subscriber status (e.g. detached, idle, connected)        . . .        
In order to manage subscription related information the core network maintains one or more registers in which e.g. the mentioned pieces of subscriber information may be stored. Such registers are, for example, HLR (Home Location Register) and VLR (Visitor Location Register). The HLR contains information about the subscribers' identity, his telephone number, associated services and general information about the location of the subscriber. The VLR, in turn, contains the exact location of all mobile subscribers currently present in the service area of a mobility management entity, such as MSC or MME, of the mobile communication network in question. This information is necessary to route a call correctly in the radio access network. The above mentioned network element names are examples and may vary according to a network technology.
The subscriber registers get typically updated in a context of location update procedure in which information on the location of the subscriber is stored in the register in question. Some examples of the occasions when the location update is performed are an attachment of the subscription to a mobile communication network and periodic or random location update procedures e.g. when the subscription moves from one location area to another and initiates the update procedure towards the network.
As described above the registrations of subscribers in the registers are normal operations of the mobile communication network. However, it may happen that the subscriber is registered in a plurality of registers of one or more mobile communication networks at the same time even if there exist procedures which aim to prevent such a double registration. An example of such a situation is that a terminal device representing the subscriber in the network terminates, for any reason, the location update procedure towards a certain mobility management entity, but the same terminal device still continues an operation towards a register, such as to a HLR. This is misoperation due to the fact that the termination of the location update procedure shall cause canceling of connection both to the mobility management entity and to the register. Now, as the subscription is maintained registered in the first register it may happen that the subscription gets also registered in another register in the same or in another network when the terminal device initiates a location update, or e.g. an attachment, to another mobility management entity and register. As a result a double registration is generated. The above described situation may e.g. happen in a traffic burst situation which may cause the mobility management entity to dismiss signaling messages in the network in order to release resources for handling the traffic burst situation and, as a result, the double registration occurs. Generally speaking the dismiss of signaling messages may occur when there exist breaks in signaling network, for instance. Naturally the registration may occur in more than two registers for the same reasons.
In view of the foregoing there is a need to establish solutions for solving, at least in part, the above described situations.